Research into flows in turbine blade seals. Part III: Numerical calculations versus experiment

Experimental and theoretical investigations of the pressure field in the shroud clearance were performed on a one-stage air model turbine of the impulse type. Measurements of pressure distribution were carried out for various rotor speeds and turbine loads. 3D calculations of flows in this turbine were performed using the FLUENT CFD code. The calculations were carried out for variants which had been measured experimentally. The experimental data have been compared to theoretical results obtained with 3D codes for turbomachinery calculations. The Sliding Mesh and Multiple Reference methods have given very similar results of average values of pressure distribution and the velocity field in the shroud clearance. These results correspond to the experimental data. The pressure pulsations were determined only by the Sliding Mesh method, and these results have also been compared with the experiment. Stage flow calculations carried by the Sliding Mesh method with a structural shroud mesh and with a minimum number of 2-2.5 million cells have given a range of non-stationary pressure pulsations corresponding to the experimental data.